add flag to flatten a single-value array

[flowchartsman]

I'm currently using this library to create plists for launchd. In a couple of locations, the specification says <dictionary [of something] or array of dictionaries [of the same thing]>. I can't imagine launchd is the only place to do this. It would be nice to be able to have a flag flattensingle such that, given

type Foo map[string]string

type Dict struct {
    Bar []Foo `plist:",omitempty,flattensingle"`
}

func main() {
    d := Dict{
        Bar: []Foo{
            Foo{
                "name": "one",
                "num":  "two",
            },
        },
    }

    o, e := plist.MarshalIndent(d, plist.XMLFormat, "    ")
    fmt.Println(e)
    fmt.Println(string(o))
}

The output would be

<plist version="1.0">
    <dict>
        <key>Bar</key>
        <dict>
            <key>name</key>
            <string>one</string>
            <key>num</key>
            <string>two</string>
        </dict>
    </dict>
</plist>

Rather than what it is now:

<plist version="1.0">
    <dict>
        <key>Bar</key>
        <array>
            <dict>
                <key>name</key>
                <string>one</string>
                <key>num</key>
                <string>two</string>
            </dict>
        </array>
    </dict>
</plist>

[DHowett]

That's a cool feature. 👍! I do, however, have to ask: Will launchd be upset if it gets a single-element array?

[flowchartsman]

A great question, and one I intend to test shortly. If it does, that's your use-case right there. If not, this could still be useful, but could also be backlogged.

[DHowett]

@alaska Did you ever test how launchd reacts to single-element arrays? I'm looking at working on plist package improvements, and I'd like to prioritize my open issues. 😄

[flowchartsman]

I haven't had the time to dig into this. I'll try and break some time off this weekend.

[DHowett]

The changes in 221fc98 should address this. I added an example (well, a test case) for an array that is serialized as a single object or an array depending on how long it is.

[DHowett]

That example is here.